There is a clear need in industry for improved waste liquid containment in many industries that chemically treat materials and, as a by-product of the treatment process, produce aggressive liquids which need to be contained in reservoirs. These aggressive (highly acidic or highly alkaline) liquids or liquid/solid waste materials cannot be disposed of by burial because they might permeate through soil and contaminate ground water supplies, and therefore, must be contained by placing a liquid barrier beneath the waste to prevent the waste from permeating the barrier. Particularly troublesome are waste materials that are strongly alkaline liquids, such as those resulting from the processing of mineral ores, particularly bauxite ores.
Geosynthetic clay liners, for the most part, have been found to provide less than adequate barrier (hydraulic performance) to high pH (alkaline) waste liquids containing high concentrations of ionic salts, particularly in the mineral ore processing industries.
Previous attempts to provide clay with improved hydraulic performance against permeation of highly ionic waste liquids have included the addition of a silica component containing free silica or a siliceous material to protect the clay from dissolution (WO 2009/023915); adding an anionic polymer solution to the clay, followed by drying (WO 2012/025564 and U.S. Pat. No. 7,026,385; US 2012/0219566 A1 and 2012/0219367 A1); and polymerizing polymers, in-situ, using a blend of clay and monomers, within the confines of a GCL (U.S. Pat. No. 6,737,472 B2).